Don't Leave Me Like This
by dandelioness
Summary: In which Castiel is sent to a high school AU. Starts off with crack, ends with "Swan Song." Thus, spoilers through the end of season five. Title from TaySwift's "Haunted" because of many reasons.


Castiel has no idea where he's been sent, nor how, with his dwindling powers, he's supposed to get back.

Dwindling powers?

No. No powers, apparently. Wherever he is, the journey has either sapped the last of his grace, or there is simply no magic here. Neither is precisely a comforting thought. He is, at least, alive and bodily whole and entirely clothed, overcoat and all, which is unexpected.

All the same, he has to make an effort not to panic when he realizes he has no way of getting home.

Such efforts are assisted by the slightly more immediately alarming prospect of the young man staring at Castiel from across the room he has just found himself in. The boy is sitting on a neatly made bed, reading a book, something Vonnegut that Castiel remembers Dean explaining once.

Well, the boy had been reading a book. Now he's staring at Castiel, blue eyes wide with wonder and, yes, a little bit of fear.

If Castiel didn't know any better, he would think he is staring down a teenaged version of Jimmy Novak. Castiel does know better. Something in those eyes makes him know that he's staring, not at a teenaged Jimmy Novak, but rather a teenaged, human version of himself.

"Well," Castiel says into the stunned silence. 'This is unexpected."

...

Cas thinks that's probably the understatement of the century. He was just sitting in his room on a Saturday morning reading _Slaughterhouse Five_ (Dean does this thing where he 'aggressively recommends' books to Cas, which basically means that he shoves books into Cas' hands and verbally harasses him until they get read), just trying to pass the time before Dean himself is supposed to make an appearance this afternoon. And now there is a strange thirty-ish year old man in a dirty trench coat who has literally appeared from nowhere in the middle of his bedroom and looks uncomfortably familiar.

"What," is all Cas manages to say, and he wonders vaguely if he's starting to pick up some of Dean's classic eloquence.

"I apologize for the intrusion," Trench Coat says, looking annoyed and more than a little uncomfortable, "I have no idea how or why I am here, nor how to leave. It is most inconvenient."

Right. Inconvenient.

"Pardon my French, but who the fuck are you?" Cas asks, setting his book down with slightly shaking hands. Trench Coat pauses what he's doing – mostly looking around like a caged animal even though the door is right behind him – and blinks at Cas in surprise and possibly confusion.

"The word fuck, despite its Latin origins, is not actually French – but that's a figure of speech, isn't it." He frowns, like he's remembering something, before focusing on Cas again. "My name is Castiel."

Cas laughs, and it sounds false and hollow to his own ears. "Of course it is." Then, because he and Dean watch too much sci-fi, "Are you from the future?"

Castiel tilts his head and actually has to think about it. "I don't believe so. What year is it?"

"2010."

"No, I'm not from the future."

"Okay."

The two Castiels go back to the kind of awkward silence that can only happen when an alternate universe version of yourself appears in your bedroom on a Saturday morning.

"Okay, so if you're not from the future, why are you twice my age?" Cas blurts out when he gets tired of Castiel staring at him. (Dean says Cas has a staring problem, but really, Cas has _nothing_ on Trench Coat.)

Castiel blinks at him. "I imagine I am much more than twice your age, as I am several millennia old."

Cas chokes on, well, on nothing. "What," he says again.

"And I expect the age difference has something to do with disparate timelines in our respective universes," Castiel continues as though Cas hadn't said anything, as though this were a completely normal conversation. Which, for the record, it isn't. Cas is socially stunted, he knows that, but even he is capable of grasping that this is some fucked up social interaction right here.

"Are you human?" he asks faintly, because it seems like a reasonable question, and well isn't that swell.

"No. I'm an angel of the Lord." But something about this (completely outlandish) statement apparently doesn't ring true to Castiel, because he frowns and then continues. "Well, probably still an angel, although I appear to be currently without any power whatever, and my grace has been dwindling overall of late, and I am in all likelihood, Falling. And perhaps not so much an angel of the Lord, as I have rebelled against Heaven in an attempt to prevent the oncoming apocalypse. An apocalypse which God apparently does not consider 'his problem.'"

And angels (or probably-angels, of the Lord or otherwise), Cas decides, should not be allowed to use air quotes, because it…it just is unacceptable. He has a thousand questions, of course, about God and angels and the apocalypse, really? but all Cas manages to say is, "Maybe you'd better sit down," and gestures to the wobbly chair at his desk. Castiel sits, straight-backed and eerily still, hands folded in his lap. "I'm Cas, by the way. Cas Milton. But somehow I feel like you already knew that."

...

Two hours later, Castiel has learned essentially the entire personal history of this human Cas – he is eighteen years old, a senior in high school, who lives with his parents and sister Anna, who he considers his twin even though she is their parents' biological child and he is adopted. Most importantly, to Castiel, at least, he knows the Winchesters.

In return, Castiel has given Cas a brief history of himself – of pulling Dean from Hell, of Jimmy Novak, of the end of the world. He doesn't mention the way he and Dean parted; doesn't mention the harsh words or the sigil carved into his own chest. Cas takes it all in stride, sometimes going pale, or gripping his knees with white-knuckled hands, but he nods and stays calm.

"I mean, I cognitively understand that what you've been through is real, but to me – it's just a story. I don't have to live with it," he explains with a shrug when Castiel remarks on his composure.

They have awkwardly fallen back into silence, Castiel trying to feel for any vestiges of grace or contact with his own world, when the door of Cas' room bursts open and another teenage boy bursts into the room, shining with an energy that is whole and pure and achingly familiar.

"Cas, get off your ass because you are not sitting around reading all day when your parents are out of town," Dean Winchester says, grinning as he flops down next to Cas anyway, pausing only to kiss the boy full on the mouth before he's sprawled over most of the bed. "Or," Dean continues with a grin, apparently oblivious to Castiel's presence, "We can just stay here."

Castiel feels his whole body tense. Well. This is something Cas Milton neglected to mention.

Apparently feeling the awkwardness of the situation, Cas clears his throat and says, "Dean, what would you do if I told you that I met the obscure angel of Thursday I'm named for and he is essentially me from a parallel universe where the world is ending?"

Dean props himself up on one elbow, still grinning. "Why, do you think it's something you're likely to say?"

Cas looks helplessly to Castiel, where he still sits at the desk in the corner. With a sigh, Castiel stands and takes a step forward. "Hello, Dean."

"Jesus mother of fuck," Dean shouts, and promptly flails himself off the bed in shock.

Cas sighs again. "Apparently, you'd fall off the bed."

...

Castiel hadn't wanted anyone else to know of his presence in this universe, but Cas had insisted that Dean, at least, deserved to know. Which is true, in Cas' eyes at least, but he's also a little selfish in that he cannot deal with this madness alone. And besides, he has no idea how to get rid of angel-Castiel, so they clearly need someone to brainstorm with them, and Cas seriously knows very few people who are smarter or better at problem-solving than his boyfriend.

Not that he's biased.

Dean takes the news surprisingly well, even interrogating Castiel more thoroughly than Cas had, emoting in all the right places in a way that Cas hasn't managed to do through the shock. He's absurdly pleased with the idea of him and Sam hunting down demons and vampires and ghosts, laughing about how much of a badass he must be; he clenches his jaw and nods once when he finds out a demon killed both his parents. The only time Dean comes close to losing his cool is when he coerces Castiel into revealing that Dean sold his soul to a demon because Sam was murdered.

"Did it work?" Dean growls out, and Castiel just nods, something going soft in his eyes. "Good." Dean has no reaction to being told he spent forty years in Hell, because Sam is alive, and if Cas is a little bit more in love with Dean because of it, well, that's alright. Kind of horrible and tragic, but alright; and besides, it sounds like they've gotten nothing on the lives of Castiel and his Dean.

When Castiel is finally done talking, Dean collapses backwards into Cas' lap, giving a soft, contented hum when Cas absentmindedly runs his fingers through Dean's hair. Castiel tenses at the actions, like he did when Dean first came in. Dean notices and frowns at the angel before rolling his eyes and looking up at Cas.

"This sounds like something out of one of Becky's internet stories," he jokes, and Cas' hand stills in his hair. Dean must see something on his face, because his smile falls and he says, "No, Cas. Absolutely not. We are not – oh god, we are, aren't we?"

Cas nods. "You have to admit, she would be the expert here."

Dean groans. "Fine. But you have to call her."

Cas just shakes his head and gets out his phone.

...

Seeing a young version of himself is unnerving enough, but Dean – this Dean Winchester isn't just young. He is _whole_ in a way that Castiel has never seen his Dean be. This Dean was raised by Mary and John (and later, just Mary, it seems – from what Cas has said, it sounds as though John left some years ago). This Dean didn't have to raise his brother, didn't have to watch Sam die again and again, didn't sell his soul. This Dean has never been to Hell. And yet.

And yet he still has Castiel.

Castiel chooses not to dwell on that. He is luckily distracted by the entrance of Sam, who is possibly the most striking contrast to Castiel's own universe yet. This Sam is barely fourteen, all awkward angles and enthusiasm, without a trace of the demonic taint that darkens his soul back at home. And, most noticeably, perhaps, this Sam is very short.

He is also accompanied by a tiny bouncing blonde with a face full of an alarming amount of orthodontic gear and the biggest eyes Castiel has ever seen. For a moment, when she first sees him, Castiel fears they will fall out of her face.

"Oh, this is so weird," Sam says, looking between the two Castiels with a completely bemused expression.

"Oh yeah, you've definitely got some serious AU stuff going on here," the girl says, and immediately plops herself on the floor in the middle of the room. Dragging out a bulky laptop from her garishly bright backpack, she looks up at Castiel expectantly. "I'm gonna need a history from you and a comparative look at your primary relationships in both universes before I can figure out why you're here and therefore how to send you back."

Castiel just blinks down at her. "Who are you?" Behind him, Dean snorts and mutters something along the lines of, "real tactful, there, Cas" and Cas tells Dean to shut up. The girl just narrows her eyes at him and then starts typing something into her computer. It's Sam who finally answers, blushing.

"This is, uh, this is my girlfriend, Becky Rosen." Castiel nods, but Sam is still staring. "Are you really an angel or was Dean making that up to make fun of me?"

"I'm an angel. Or I was," he adds as an afterthought. "That much is no longer quite clear to me."

Sam opens his mouth again, probably to ask more questions, if he in any way resembles his counterpart as Castiel knows him, but Becky looks up with a stern expression. "Sam, I cannot have you fanboying while I'm trying to work. Actually, all of you, out. Except for angel-Cas. You stay."

After much grumbling about how Becky shouldn't be allowed to kick people out of someone else's bedroom, they all leave. It's silent for some time, except for the unnecessarily loud clacking of Becky's keyboard. She is entirely absorbed, and doesn't seem to notice Castiel's presence at all. It's almost twenty minutes before her head snaps up.

"Okay, I've got all the best minds working on this, except for a couple who live in Australia and are asleep, but nothing we can do about that. Sit down, and let's get started."

If Castiel thought that Cas or Dean had many questions about his universe, their inquiries pale next to Becky's in quantity alone. She wants to know about the structure of Heaven, about the millennia he's lived prior to meeting Dean. She wants to know about magic and demons and monsters and hunters. She wants to know about Castiel's family, about his relationships with his siblings, about Anna, about Uriel, about Zachariah. She wants to know about Chuck and Raphael and defying prophecy and dying. She wants to know about Sam – she types viciously when Castiel speaks of Ruby, but slightly less so when she finds out how Ruby died.

But mostly, she wants to know about Dean. Seeing Dean in Hell, trying to communicate with him, meeting him in the barn. Pushing and fighting and learning to trust and choosing free will. Rebelling for Dean. Falling for Dean. All of it, for Dean.

"Why do you keep asking about Dean?" he finally asks. They've been at this for almost two hours, and Castiel's throat is dry and uncomfortable from talking.

"Because he's your common denominator," Becky replies, shaking her head like it's obvious. His confusion must show on his face, because she sighs and explains, "Look, you have a lot of people in common between universes, right? Mr. Singer, the Winchesters, the Harvelles, your sister Anna.

"But you never met Mr. and Mrs. Winchester, your relationship with Mr. Singer is minor, and the Harvelles and Anna are dead. Your relationship with Sam is different than here – here, he's still like a little brother, someone you have to watch out for, not an equal – not to mention, not strained because of the whole demon blood fiasco.

"But Dean – he's your best friend in both universes, easily your primary relationship. He influences you more than any other individual in your life, and he anchors you in your world."

Castiel can't deny it, nor does he want to. All the same – "Dean and I – where I come from, we're not – "

"Together? Yeah, that's kinda weird to me – I ship it like burning, bee-tee-dubs – but I think in the end it's kinda a non-issue. At least, practically." She frowns at the laptop screen for a moment, then snaps it shut and stands. "I think I've got something, so I wanna call the others back in, 'kay?"

Castiel nods, standing as well. As Becky turns to open the bedroom door, he finds himself speaking. "Wait." She turns, looking up with large, curious eyes. "The Harvelles – Anna – they're really still alive?"

Becky's face collapses a little as she nods, and her eyes fill with tears. "That's the best part of high school AUs," she says, trying to smile. "Everyone's alive." She hesitates for a moment, then unceremoniously flings both her arms around Castiel's middle, laptop and all.

...

"Okay," Becky announces once she's allowed everyone back into Cas' bedroom. "I think I've figured out the basics of what's going on – I had some help from the _Merlin_ fandom because they've got the most extensive AU system of any fandom I know – " When Dean opens his mouth to protest, Becky holds up her hand. "I told them it was for a fic I was writing, don't look at me like that, Winchester. Really, I have a brain.

"Anyway, here's what we have. For the sake of this discussion, angel-Castiel's universe is going to be considered canon." Becky, Cas thinks, looks a little too excited about this prospect, but then, when doesn't Becky look a little too intense? "We are therefore an AU – and alternate universe fanfiction. A high school AU, to be precise, which makes sense – everyone's alive and the main ship," and here she nods to Dean and Cas, where they're seated once more on Cas' bed, Dean's head in Cas' lap, "is together, even though they're not canonically."

"Wait, what?" Dean says, sitting up so fast he almost brains himself on Cas' chin. Becky rolls her eyes with an expression that says, _why do I have to explain everything to these idiots._

"A ship is a romantic pairing – in this case, you and Cas. Our world is more clearly the AU, because while angel-Castiel and his Dean Winchester are barely friends in his world, you and Cas are dating here. Which is actually a good thing, because it gives us an idea as to why Cas is here in the first place – "

"What do you mean, 'barely friends?'" Dean demands, looking more upset than he has since he found out Sam died in the other universe, and glaring at Castiel. Cas is taken aback by how strongly Dean's reacting; Becky, on the other hand, looks murderous at having been interrupted in her moment of glory, and Sam, well, Sam just looks like he's wondering how this became his life.

Castiel frowns. "Dean, you and I are allies in a war. I have a great regard for you – for him, but at the best of times our relationship is described as friendship."

Dean looks like he's been slapped. Becky takes the opportunity to continue what she had been saying. "_Anyway_, like I was saying, this gives us a pretty good idea of why Cas is here." She turns to Castiel. "In fic, or even in canon, something like this only happens when the main character needs to learn something. We can assume that your Dean is also getting something out of this, but I'm guessing you need to learn something from our Dean and our Cas – which I will leave you to in just a minute."

Becky turns to Castiel, and really, Cas thinks, she's loving this. Not that Cas blames her – Dean finds Becky incredibly obnoxious, so it's not often she and Sam get to hang out with Dean and Cas, let alone for Becky to be treated like she's a competent human being. (To be fair, Becky isn't exactly kind to Dean, either – she once summarized him as 'underwhelming' to his face. Which is frankly the opposite of the problem with Becky.)

"Okay, so in the past, you and Dean have communicated in times of distress through prayer and his dreams. I would recommend trying to access your connection to your Dean through this Dean; there's got to be some version of that bond between you guys, some ghost of it. Enough to form a connection anyway. I hope." She frowns for a minute before brightening. "Anyways, I hope that helps, Sam and I have to go now because we have a date and as awesome as it is to find out we're basically fanfiction of someone else's life, I have been waiting for this all week and seriously nothing takes priority over date night with Sam."

Sam turns bright red as Becky gathers him and her laptop and turns to go. Before she does, she turns to Castiel one more time and wraps him tightly in a hug. It's comical, Cas thinks, since Castiel is easily half a foot taller than Becky, and stiff as a board to boot. But he seems to relax slightly at her touch, and even smiles slightly when she whispers something into the shoulder of his trench coat. Dean raises his eyebrows at Cas, who just shakes his head.

Today is very, very weird.

...

"Too bad we don't have a broken transporter beam to access the mirror universe," Dean jokes awkwardly once Becky and Sam have gone.

Castiel just blinks at him and says, "I don't understand that reference," in frustration at the same time Cas says, "But then we'd just end up with Cas-with-a-beard."

Dean stares. "Seriously, man, I've never made you watch _Star Trek_? That is like, the basics, right there."

Castiel feels himself tense. "I've tried to explain, Dean, you and I are not close where I'm from. We're not – " he makes an aborted half-gesture towards the two boys on the bed, and Dean looks a little pissed.

"Is it because we're both dudes?"

"Dean – " Cas tries to say, eyebrows raised, but Dean talks over him.

"What, you're some angel of the Lord now and so you've got a problem with two guys being together? Is that what this is about?"

"I am utterly indifferent to sexual orientation," Castiel says tersely. Cas gives him a sympathetic look.

"Dean, look, things are just different there – here, we grew up together, but Castiel and his Dean met under very different circumstances, it makes sense – " but he cuts off as Dean's face falls.

"Oh," he says, and looks down at his hands. "I get it. Hell. The whole part where he – where _I_ – broke and – and – " he laughs darkly, and there's something there too close to Castiel's Dean for comfort. "Yeah, no wonder you want nothing to do with me, you're way too good for me." Cas reaches out and holds Dean's hand.

"No," Castiel says, so strongly that both boys look at him. "No, Dean, you – " He doesn't know how to explain this to this boy, to explain everything Dean Winchester means; not when he can't manage to communicate to the Dean who actually matters. He clenches his fists once, twice. "I rebelled from Heaven for him. I defied fate for him. I _died_ for him. And I have stayed by his side even after he and Sam destroyed the world, after he gave up. There is _nothing_, no part of myself I would deny Dean Winchester."

Dean looks completely flabbergasted by this speech, and Castiel cannot blame him. "Then, why – "

"Because Dean does not consider me with the same regard you feel for Cas. We are allies. We are friends. Nothing more."

"No." It's Dean's turn to say it now, it seems. There's a fierce look in his eyes that Castiel associates with Dean's protectiveness of Sam, of Bobby – of family. "There're two things I know for certain: One, Bert and Ernie are gay; and two, I am stupid in love with you no matter what universe I'm in, I guarantee it." Dean's ferocity falters at whatever he sees on Castiel's face. "What?"

Castiel shakes his head. "My Dean said something similar to me not very long ago – 'There are two things I know for certain: One, Bert and Ernie are gay. And two, you are not dying a virgin, not on my watch.'"

Cas buries his face in his hands, apparently overcome by the hopelessness of Dean Winchester, but Dean brightens. "See? I told you – "

"At which point," Castiel continues, eyebrow raised, "He took me to a brothel."

Cas starts laughing and Dean just groans. "Of fucking course I did."

...

They're not very good at brainstorming without Becky around. Dean's getting progressively more irritable as time goes on because he had planned on spending today taking advantage of the fact that Cas' parents were gone with Anna on a college visit; Castiel is getting restless because, well, he's stuck in a horrible alternate dimension, who wouldn't be? and Cas' brain just hurts. It's coming on five o'clock when Castiel stops pacing and starts staring at Dean.

"What?" Dean snaps after the staring goes on in silence for almost a minute.

"I think I can hear you – him," Castiel says, eyes widening. "It's very faint, but…"

"What am I saying?" Dean asks urgently.

"You're…praying that I'm alright. And you want me to come back."

Dean breathes a shaky sigh of something like relief, and says, "Well, yeah, of course. Question is, how do we get you there?"

"The bond," Cas says, speaking for the first time in what feels like hours. Both Dean and Castiel turn to look at him. "You said you and Dean have some kind of 'profound bond' thing going on, right?" Cas ignores when Dean winces at his use of air quotes. Maybe that's something to the two Castiels have in common. Huh. "And Becky was saying that you have to learn from us, right?" he continues, gesturing to himself and Dean. Castiel nods slowly. "Well, if it were us, I'd use my connection with Dean to pull me back. Use him like an anchor."

"That's smart, Cas," Dean says, and Cas rolls his eyes.

"It's been known to happen."

"But I can hardly hear him," Castiel says, a slight edge of desperation to his voice. "Unless…" He takes a step toward Dean, arm outstretched, and then stops. "May I?"

Dean, frowning, nods, and Castiel reaches out and fits his hand over Dean's upper arm. At the contact, both their eyes go wide, and Cas swears the lights in the room dim for a second before Castiel steps back, something almost like a smile on his face.

"I can go back," he says firmly, confident in a way Cas hasn't heard from him much since he arrived. "The connection – I don't have access to my power, I am cut off from the Host, but someone – someone is trying to pull me back."

Cas nods, letting out an unconscious sigh of relief. This whole freak adventure is almost over, then. "So if you just – " he waves vaguely at Dean, who's got a hand on his shoulder and a look of awe still on his face as he stares at Castiel, " – you can get back?"

Castiel nods. Hesitating, he looks between the two boys. "Thank you for your assistance. I…it is good to know that, here, at least…"

"Yeah," Cas says, because he knows what Castiel is hesitant to say. _Here, you're happy. Here, you're alive. Here, you have each other._ It's that last, more than anything else, Cas thinks, that sparks the flash of longing in Castiel's eyes.

"Wait," Dean says suddenly, drawn out of whatever reverie he's been in. He scrambles off the bed and toward Cas' desk. "Wait, I want – could you give something to him for me? To me, I mean?"

Castiel looks startled, but he nods, and both of them watch as Dean rips a scrap of paper from one of Cas' notebooks and scribbles something down. Cas doesn't have to look at the angel version of himself to know the slight frown, the crease between his eyebrows. It's eerie and familiar and frankly Cas can't wait for it to be over.

Dean shoves the paper into Castiel's hand with a desperate look, searching Castiel's face for something before nodding and letting go. "Let's do this."

It's almost anticlimactic, really. Castiel reaches a hand toward Dean again, but this time the moment he touches Dean's shoulder, he's gone. Dean and Cas are left blinking at empty air before they turn to each other. Dean's expression is essentially what Cas is feeling – slightly shell-shocked and half-hysterically amused. They stay like that for almost a full minute before Dean speaks.

"How long d'you think before your parents and Anna get back?"

"Oh, a couple hours, at least."

"Good." Dean grins. "Wanna make use of that time?"

"God, yes," Cas growls, and they tumble onto the bed.

...

When he gets back, this is what he does not have: his power. It's like a gaping chasm where the Host should be, combined with a claustrophobic sense of being confined to his empty vessel. Without his power, though, without his grace, with Jimmy gone, dead since the confrontation at Chuck's almost a year ago – it's no longer a vessel, Castiel realizes. It's his body. He's not altogether sure how he feels about that.

They tell him they found him, bloody and unconscious and apparently brain-dead, on a shrimping boat off of Delacroix.

This is what he does have: a headache, a bug bite, and (small miracles) the note given him by the other Dean, somehow still in the pocket of his coat.

This Dean, though, _his_ Dean, is facing an apocalypse, so Castiel tucks the note back into his pocket and gets on a bus. Before he does, he tells Dean, "I owe you an apology. You are not the burnt and broken shell of a man I believed you to be."

...

"This is what they mean by the 'eleventh hour,' right?" he asks Bobby, even though he already knows the answer. His fingers brush the note in his pocket.

...

"I wasn't dead," he says suddenly, into the quiet. The time isn't right; but Sam is gone, now, and the time will never be right. There is not enough time left for it to be right. He can feel Dean look over at him in surprise, but for once, Castiel doesn't return his gaze. "Before, after the angels – I wasn't dead. Or perhaps I was, but I wasn't in Heaven. Or Hell," he adds hurriedly when Dean draws a sharp breath.

"Then where were you?" Dean asks, voice drawn tight with anxiety, when Castiel doesn't continue right away. He hears the edge of accusation in the tone, one Dean probably doesn't even realize is there. It sounds like, _we needed you here, I needed you here, where were you_?

"I was…it appeared to be some kind of parallel universe."

"That's a thing?" Dean blurts in surprise, and Castiel has to suppress a smile. Of course, no matter the unbelievable things he sees on a daily basis, it would never occur to Dean to believe in alternate realities. "How did you know?"

"I met you," Cas responds simply. "And Sam, and a young girl named Becky Rosen. And myself."

"What the hell was Becky doing there?"

"She and Sam were dating." Dean chokes on the air, so Castiel simply continues over him. "They were all teenagers. It was very strange."

"Teenagers? You too?" Castiel nods. "Human?"

"Becky called it a…'high school AU.'" He pretends not to notice Dean wincing at the air quotes.

"Like that fanfiction shit people wrote about me and Sam, because of Chuck's books."

"Yes." Silence, because Castiel isn't sure how to tell Dean what he wants to tell him, what he has to tell him, because Castiel has a promise to keep.

"Well, at least whoever authored that particular universe didn't try to stick me and Sam together," Dean grumbles.

"Yes," Castiel agrees. And then, drawing a deep breath, "Dean – the other Dean – he wanted me to give you something." Dean looks up again, sharply, but Castiel continues to stare straight ahead. "But first, I have to tell you…in that other world, you and I – Dean and Cas – they were together."

Silence again. Dean clears his throat, still staring intently at Castiel. "Like, together, together? Dating?" Castiel nods. "You and I were dating?" Dean seems to be in shock. Castiel just reaches into his pocket and hands Dean the crumpled piece of looseleaf.

He shouldn't know what it says, but he does. He read it on the bus ride, read it until he memorized it. It was…comforting to read those words, comforting to think that perhaps, just perhaps, _his_ Dean might feel something of the same. It is poor comfort now, knowing how soon it will all end.

_Listen up, asshole,_ it begins. _So Cas – your Cas, I guess, not mine – he told us about your universe. Sounds like a shitshow, dude, I'm sorry. But stop using it as an excuse._

_ Face it, other than your family, Cas is the best thing to ever happen to you. And you love the stupid bastard, don't try denying it. If it's the gay thing that's bothering you, whatever man, Sam doesn't care and what Dad never knows won't hurt him. If it helps, Mom loves Cas._

_ And Cas, he's just waiting on you._

_ So get your shit together and – this is the important part – __don't fuck this up__._

_ PS – good luck with the apocalypse_

Castiel does turn to look at Dean now, to watch him read the note. To watch as his mouth opens slightly in surprise before his face closes off entirely, becoming blank, becoming stone. Perhaps if Castiel were still an angel, he'd be able to tell what Dean is feeling. But he isn't. And he can't.

"Cas," Dean says quietly after what feels like forever, "Cas, I can't, you know I can't – " he breaks off, refusing to look up from the scrap now clutched white-knuckled in his hands. "Sammy's gone, the Devil's wearing him, the goddamn world is ending – I can't."

"And if it weren't?" Castiel asks, equally quietly, before he can stop himself, knowing that the question isn't fair. "If the world weren't ending, Dean?"

Dean doesn't say anything. Doesn't blink, doesn't move. Castiel nods, and stands, because he should have known. This is his Dean, and his Dean has just lost his brother to the devil. His Dean is going to probably get himself killed before the world ends in a mad effort to get his brother back.

He walks away without saying anything further. Behind him, he thinks he hears Dean offer a soft, "Cas – " but he pretends he didn't, and keeps walking.

...

"If we've already lost, I guess I got nothing left to lose," Dean spits, angry and grieving and lost.

Castiel doesn't say, _but there are people who will have to lose you_. Castiel does say, "The only thing you're going to see out there is Michael killing your brother."

Dean looks him in the eye, desperate and decided and lost to Castiel already, "Well, then I ain't gonna let him die alone."

...

When Castiel gets into the truck beside Bobby and they race to reach the cemetery, they both know they aren't coming back. It is no longer about saving the world or even about saving Dean; it's not about stopping Michael and Lucifer. The end is inevitable. Dimly, Castiel hopes that the other universe survives the end of this one.

When he launches a bottle of flaming holy oil at Michael, Castiel knows it is one of his more reckless decisions. Still, he meets Dean's eye and says, "You've got your five minutes." Dean just stares for a second, and Castiel knows he understands why they're there.

They're not going to let him die alone.

...

Oddly, being smote by archangels doesn't seem to stick.

Castiel knows he has to go back to Heaven, now that Michael is gone. He knows that this conversation with Dean as they drive away from the cemetery is the last they will have for a long while. So, of course, they argue.

About Castiel's loyalties. About God. (Always, always about God; Dean will never be satisfied on that front, while Castiel is content not knowing, for the time being.)

"Where's my grand prize?" Dean demands, not because he wants a reward, Castiel thinks, but because he feels he's been punished instead. "All I got is my brother in a hole."

"You got what you wanted, Dean," Castiel responds quietly, even though it's not true and they both know it. What Dean wanted was his brother, whole and alive and safe. "No paradise. No hell. Just more of the same.

"What would you rather have: peace, or freedom?"

He moves to leave, because he is tired of saying goodbye to Dean, but Dean stops him with a word.

"You." It's cracked and breaking and sounds as though it were being dragged out of Dean's mouth against his will, but it's there. It holds Castiel in the passenger seat, on the edge of flight.

"Pardon?"

"I'd rather have you, Cas," Dean snaps. "I've just...Sam's gone, and I can't go back to Bobby's and I can't go to Lisa's, I know I promised Sam, but I just can't. And I can't do this alone.

"And I still don't have an answer for you, I'm sorry. I don't know if I ever will. But right now, every part of me, every fiber I've got, either wants to die or find a way to bring back my brother, bring back Sammy." Dean's voice breaks on Sam's name, and Cas aches to reach out to him. "But I won't. Because I've got a damn promise to keep."

Dean grips the steering wheel with white knuckles and stares at the road ahead with red eyes that refuse to shed a tear. Castiel sits in silence and stares at Dean and tries to think of something to say.

"I mean I guess I get it. Even after everything, those dicks are still your family or whatever, but I thought we were, too. And I don't got much family left, Cas. So please. Just say you'll stick around."

"I have to return to Heaven, Dean," Castiel says at last, soft, gentle. "But – " _There is nothing, no part of myself I would deny Dean Winchester_ "I will come back."

Dean just nods, mouth thin, jaw tight, looking somehow more dejected than before.

"Dean." And Dean looks over at him, meeting Castiel's eyes in the dark of the car (which should be worrisome, as it means Dean's eyes are not on the road). "I will come back. I swear to you."

Something in Dean's face relaxes, and he nods again before turning back to the road. Castiel nods back, even though is no longer looking at him, and spreads his wings once more.

He will return to Heaven, help to order the chaos there, and soon – soon, he will come home.


End file.
